The Joker pays a visit to Commissioner Gordon's office @ Police HQ and swipes a Rare Art Map. Alerted, Batman and Robin deduce that The Clown Prince Of Crime is plotting to commit 12 crimes based loosely on astrological signs of the zodiac and that he committed the first Zodiac Crime already by stealing the Rare Art Map, whose initials stand for the sign of The Ram (Aries!). Meanwhile, back at his hideout Joker clues the recently arrived (rather, packaged and shipped!) Penguin into his nefarious astrological plan. He then gives a false clue to The Dynamic Duo to the effect that "Taurus The Bull is next on my show," and "You'll be singing a song of woe!" Batman and Robin deduce that Joker was telling them a lot of bull, believing that The Homicidal Harlequin's true objective involves kidnapping a famous brother-and-sister singing duo named The Twins (Gemini!), who sing a song of woe, and they rush to their aid. Unknown to our Duo, the singing duet have already been replaced by Joker's aides, and that Blackbird Of Prey, The Penguin, is waiting in the wings to ensnare The Crusaders.

Arriving at the studio, The Caped Crusader and The Boy Wonder are led outside, where Penguin escapes on Joker's Boom Bug. Racing to The Batmobile, The Dynamic Duo chase the bizarre truck, but lose The Penguin, who cleverly lifts himself off with the aid of his trusty bumbershoot and an overhead wire. While Batman and Robin are led astray, The Joker and his shapely aide, Venus, make off with the true twins: the famous Twin Diamonds! Returning to The Batcave, The Caped Crusader learns the location of The Joker's hideout by analyzing the long wig left behind by Venus at the studio when she masqueraded as one of The Twins. Arriving at the hideout, Batman and Robin find the place deserted save for Venus, who falls for Batman and agrees to help him and Robin snare The Joker. She leads The Dynamic Duo to the opera house, where The Dastardly Duo, Joker and Penguin, plans to commit 2 Zodiac Crimes: the kidnapping of Leo Crustash (Leo The Lion and Crustacean The Crab!!). A fight ensues, but Joker and his minions escape, abandoning Penguin to the fate of the authorities. Figuring that The Homicidal Harlequin is scheming to pilfer a masterpiece entitled Virgin Bereaved (Virgo The Virgin!), Batman and Robin dash to The Gotham City Museum, where they are overpowered and tied down to an altar beneath a giant meteorite, which is rigged to fall on them (and turn them into tomato paste!) when its supporting cable is severed by a revolving piece of thermite attached to a planetary mobile surrounding the great rock!